thousands separator format on df column

[metalray]

Dear Python Experts,
 
I an trying to convert my PopEst column so a thousands separator gets added.
 

def thirteen():
    Top15 = answer_one()
    Top15['PopEst'] = Top15['Energy Supply'] / Top15['Energy Supply per Capita']
    PopEst = Top15.ix[:,20]
    return PopEst     #'{:,}'.format(13213) #return '13,213'
answer_thirteen()

 
The function '{:,}'.format(13213) #return '13,213' works fine when I put a number between the parenthesis myself
but I need it applied to my dataframe column "PopEst". I could not find a way to do that.
Is that possible?
Many thanks for any hints.

[zivoni]

PopEst.apply("{:,}".format)

[wavic]

Hello!
It's a bit off topic but...
In Python 3.6 for readability you can use underscore as thousands separator. Like this: a_mil = 1_000_000. Yet this is a valid number and is threated as 1000000. More here.